Plug



FIG. 1 is a perspective view of the plug, where the reverse side is a mirror image;

FIG. 2 is a front elevation view of the plug, where the left side, right side, and rear side are mirror images;

FIG. 3 is a top plan view of the plug; and,

FIG. 4 is a bottom plan view of the plug.

The broken line showing of is included for the purpose of illustrating environment and forms no part of the claimed design. 

CLAIM The ornamental design for a plug, as shown and described. 